Agent Heather is a beautiful Interpol agent and the aide to Gadget Boy. She is a more resourceful agent and is the equivalent of Penny from Inspector Gadget, except Agent Heather is much taller than Penny and appears to be in her early 20s, and is the love interest of the inventor Myron Dabble.
She has red hair and wears a green jacket, blue trousers, a white shirt, and blue shoes. Her name is Estelle in the French version. It is revealed in Gadget Boy and the Wee Folk that her bloodline is Irish.